Grounding mechanism for magnetos



NOV- 24, 1942. w, E. scHwARzMANN ETA. 2,302,896

Y GROUNDING MECHANISMS FOR MAGNETOS Filed oct. 1s. 1941 Patented Nov. 24, 1942 2,302,896 oRoUNDlNG MECHANISM; Fon MAoNEros Wolfgang E. Schwarzmann, Charles Strniste, Agawam,

Corporation,

American Bosch Longmeadow, and Mass., assignors to Springfield,

Mass., a corporation of New York Application October 18, 1941, Serial No. 415,542

2 Claims.

This invention relates to grounding mechanisms for magnetos in electrical ignition systems for associated internal combustion engines, and particularly to such mechanisms which, upon detachment of a terminal connector from the magneto, ground the magneto to render it electrically inoperative in the system and which, upon attachment of the connector, remove the ground to restore the operativeness of the magneto. Such systems are generally disclosed in our U. S. Patents 2,253,201 and 2,281,862.

One object of the present invention is to provide such forms of grounding mechanisms in such structural combinations with magnetos as will give the possibility of alternative installations of the terminal connector with equal eiectiveness of the grounding features, whereby the connector may be installed on the magneto in such position as will more likely eliminate mechanical interferences with other devices of the power plant and also will more suitably accommodate the wiring to the electrical devices associated with the magneto.

Another object is to provide specific forms of grounding mechanisms, wherein in one form a plurality of grounding devices are provided for cooperation with the terminal connector at all its possible locations on the magneto, together with means for rendering those devices at the unused location or locations non-interfering with the devices being used at the time and preferably use- `ful for other grounding purposes also. and wherein in another form a repositioning of parts of a single grounding device renders it adaptable to different locations of the terminal connector on the magneto.

Still another object is to provide grounding mechanisms of these forms of simple, inexpensive, compact, durable construction, and which may be readily installed anddemounted and be effective in operation in all alternative positions of installation on the magneto. These and other objects and advantages will be understood from the following description taken in connection with the accompanying drawing showing the two aforesaid embodiments of the invention applied, as an example. to the housing oi a magneto with stationary ignition coil and interruptor mechanism. In the drawing,

l. is a plan view, partly in section and partly diagrammatic. showing the interrupter mechanism and having a housing accommodating a plurality of grounding devices for cooperation with a terminal connector at either of two alternative locations on the housing; Fig. 2 is a section on line 2 2 of Fig. 1; Fig. 3 shows a second embodiment in elevational view, partly in section, of an interruptor housing having grounding devices which are arranged for cooperation with a terminal connector in one location on the housing but which may be repositioned to cooperate with the connector in another location on the housing; Fig. 4 is a section on line 4-4 of Fig. 3; and Fig. 5 is a plan View on a reduced scale showing the arrangement of the terminal connector on the housing of this second embodiment.

Referring to the embodiment of Figs. 1 and 2, the reference numeral I designates the magneto housing for the interrupter mechanism which includes the mechanical interrupter mounted on the adjustable interruptor disc 2, engine driven cam 3, interrupter contacts 4 and 5, of which the latter is grounded through its bracket 6 adjustable on the disc 2, the live interrupter terminal l and the condenser 8, all as is well known. The ignition coil (not shown) is connected by wire 9 to the metal strip I0, the interruptor terminal 1 is connected to the metal strip I I, and the wire I2 from the live terminal I3 of the condenser 8 is also connected to the metal strip I0. These two strips I0 and I I are electrically connected to each other and. to the two strips of spring metal I4 and I5 by bolt I' bearing against the metal washers il which clamp the strips as shown between them and the bushings I8 of insulating material. The bushings are held apart by the metal member I9 which has a central opening at 20 for the passage freely therethrough of the bolt IS and which suspends this part of the grounding mechanism by its fastening at 2| to the metal plate 22 screwed at 23 to the housing I. The housing has for encasing the grounding mechanism a tubular extension 24 with threaded outlets at opposite ends of its bore. In the left lhand end outlet as shown in Fig. l, is mounted a detachable terminal connector 25 of well known form for the shielded wire 26 leading to the grounding switch 2l. This connector includes a spring 28 which is fastened to the conducting strands o wire 25 and which bears against the free resilient end of strip I4 with suiiicient pressure to hold it against bolt I away from the grounded housing I. as shown in full lines in Fig. 2. The terminal connector 25 thus connects the live terminals of the ignition coil and interrupter in electrical parallel to the grounding switch 21. Likewise the insulating plug 29 holds the strip I5 against bolt i6 out of contact with housing I. This plug 29 is not connected to a wire but the outlet therefor is closed by the disc 30 and nut 3|. Thus whenthe sv-.fitch 2l' is closed, the magneto is ed; but even if that switch is open, so long the connector 2E or plug 29 is not propmbled in the extension, the magneto is grounded by either or both spring strips I4, I5 in Contact with the housing i in the position shown in broken lines in Fig. 2. Upon opening the switch 2l in the former case, or upon properly installing both connector and plug when the switch is open, the ground is removed and the magneto is again rendered electrically operative to generate ignition impulses for the sparkplugs of the engine in the well known way; but until that is accomplished the magneto remains incapable of generating ignition impulses. As noted in U. S. Patent 2,258,201, this arrangement protects against accidents in starting the engine after disassembly of the grounding mechanism for inspection, repair or replacement.

If, lbecause of mechanical interference with the engine or other devices associated therewith, or in order to better accommodate the wiring from the grounding mechanism to electrical devices therefor, or for any other reason, it is desired to connect the wire to the right hand outlet of extension 24 in Fig. 1, the connector 25 is fastened in that outlet and the plug 2E), sealed by the disc and nut Si, is installed in the left hand outlet. Until both connectors are properly connected as aforesaid, and the switch 21 is open, the magneto remains grounded and therefor incapable of generating ignition impulse In the embodiment of Figs. 3 5, the metal clip 32 has a terminal 33 which .fits around a shoulder in the centrally-bored metal member 34 in electrical contact with it. To this clip is mechanically and electrically fastened the wire 35 from the ignition coil (not shown) and the wire 35 leading to the live terminal of the mechanical interruptor (not shown) of the magneto. Also in contact with this member 34 and fastened thereto in any suitable way, is the grounding spring 37 having an arm 38 adapted, when unrestrained, to flex outwardly as shown in broken lines in Fig. 4 at the right of member 34. This member 34 is held in place by the screw 3S passing freely through the bore thereof into the housing 4! but insulated from the member by the bushing 4l and washer 42 of insulating material. Held in xed angular position between the bushing and the housing by the screw 39, is a grounding clip 43 which is in electrical contact with the housing and which has a depending end 4 adapted to be engaged by the arm 33 of the grounding spring 3'! when unrestrained. This grounding spring is adapted tc be held away from the clip 43 by spring 45 of the terminal connector 43, but upon removal of the connector, the magneto is automatically grounded and maintained in that electrically inoperative condition until the connector is restored. The interrupter housing 47, in which the foregoing grounding devices are mounted, has two connector terminal outlets 48 and 4S arranged at opposite ends of the tubular extension 5l). In Fig. 5 the left one of these outlets is sealed by a nut 5|, and in the right one is mounted the terminal connector for the wire 52 which as before may lead to a grounding switch.

If, as before. on account of mechanical interference, or to better accommodate the wiring, or for any other reason, it is preferable to connect the terminal connector and wire 52 to the left hand outlet of the extension 5U, as shown in broken lines in Fig. 4, the screw 39 is loosened and the member 34 and bushing 4l are turned 180 to another position in the magneto, taking with them the grounding spring 31 and clip 4|. The connector 46 and nut 5| are interchanged, the spring 45 holding the grounding spring in its ungrounded position, as shown in broken lines at the left in Fig. 4, and the nut 5l Closing the right hand outlet. As before upon removal of the connector 45 at any time, or upon closure of a grounding switch, the magneto is grounded and rendered incapable of electrical generation of ignition impulses, as in the embodiment of Figs. 1 and 2.

Although but one embodiment of each form of grounding mechanism is disclosed herein, many modifications of each may be made within the broad interpretation of the appended claims. It is apparent that either form of grounding mechanism may be applied to any suitable type of high-tension or low-tension magneto which is associated with an engine of any number of cylinders operating on any cycle and which is driven thereby at any suitable speed ratio. Also the grounding mechanisms may have terminal connectors of any suitable type for shielded or unshielded wires connected to grounding switches or other appropriate electric devices as vibrators r starting magnetos. Furthermore, any suitable part of the magneto housing may provide two or more than two alternative outlets for the terminal connector which may mechanically and electrically cooperate with grounding mechanism electrically connected to any suitable part of the generating circuit of the magneto, such, for example, as to the live terminal of the interruptor as in Patent 2,253,201, or to the low-tension terminal of the ignition coil as in Patent 2,281,862 or to an electrical connection between the two as shown herein.

The second embodiment of this application, as disclosed in Figs. 3 and 4 of the drawingllerein, is included in our application Serial No. 462,122, filed October 15, 1942, as Figs. 5 and 6, and is covered by the claims of that application.

Having thus described our invention, what we claim is:

1. In combination; a magneto having a generating circuit and a housing arranged to accommodate a terminal connector at either of two locations; a single terminal connector which is adapted to be electrically connected to an outside electrical device and which is constructed to be mechanically fastened to the housing at either location; for each location a grounding device which when unrestrained electrically connects the generating circuit to the housing to ground it and thereby renders the generating circuit electrically inoperative and which is engaged by the terminal connector when fastened in such location to electrically connect the terminal connector to the generating circuit and to restrain that grounding device in order to remove its electrical connection to the housing; and means for restraining the grounding device at the unused location to complete the disconnection of the generating circuit from the housing and thereby render the generating circuit electrically operative.

2. In combination; a magneto having a generating circuit and a housing arranged to accommodate a terminal connector at either of two locations; a single terminal connector which is adapted to be electrically connected to an outside eelctrical device and which is constructed to be mechanically fastened to the housing at either location; for each location a grounding device which when unrestrained electrically connects the generating circuit to the housing to ground it and thereby renders the generating circuit electrically inoperative and which is engaged by the terminal connector when fastened in such location to electrically connect the terminal connector to the generating circuit and to restrain that grounding device in order to remove its electrical connection to the housing; and arranged at the unused location, an insulating plug which restrains that grounding device to complete the electrical disconnection of the generating circuit from. the housing and thereby render the generating circuit electrically operative.

WOLFGANG El. SCHWARZMANN. CHARLES STRNISTE. 

